:root {
  --bg: #f3f5f8;
  --surface: #ffffff;
  --ink: #0f172a;
  --muted: #556079;
  --line: #d7dfec;
  --primary: #0f63ff;
  --primary-strong: #0048c9;
  --teal: #11b8c8;
  --soft: #edf3ff;
  --shadow: 0 22px 55px rgba(12, 28, 68, 0.14);
}

* {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  padding: 0;
}

body {
  font-family: "Noto Sans SC", "PingFang SC", "Microsoft YaHei", sans-serif;
  color: var(--ink);
  background:
    radial-gradient(circle at 10% 8%, rgba(17, 184, 200, 0.25), transparent 34%),
    radial-gradient(circle at 88% 0%, rgba(15, 99, 255, 0.18), transparent 36%),
    var(--bg);
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 30;
  padding: 0.85rem clamp(0.9rem, 2.8vw, 2rem);
  display: flex;
  justify-content: space-between;
  align-items: center;
  backdrop-filter: blur(14px);
  background: rgba(243, 245, 248, 0.84);
  border-bottom: 1px solid rgba(215, 223, 236, 0.8);
}

.brand {
  font-family: "Space Grotesk", "Noto Sans SC", sans-serif;
  font-weight: 700;
  letter-spacing: 0.02em;
  font-size: clamp(1rem, 2.5vw, 1.26rem);
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.lang-switch {
  display: inline-flex;
  border: 1px solid #c6d7f6;
  border-radius: 999px;
  overflow: hidden;
  background: #f1f6ff;
}

.lang-btn {
  border: 0;
  background: transparent;
  color: #495c80;
  font-size: 0.82rem;
  font-weight: 700;
  padding: 0.36rem 0.58rem;
  cursor: pointer;
}

.lang-btn.is-active {
  background: #dbe8ff;
  color: #0b4ec8;
}

main {
  width: min(1120px, calc(100% - 2rem));
  margin: 1.35rem auto 0;
  display: grid;
  gap: 1.35rem;
}

.hero {
  display: grid;
  grid-template-columns: 1.24fr 0.76fr;
  gap: 1rem;
}

.hero-copy,
.hero-panel,
.features,
.gallery-card,
.download-card,
.faq-card {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 24px;
  box-shadow: var(--shadow);
}

.hero-copy {
  padding: clamp(1.15rem, 2.3vw, 1.95rem);
}

.kicker {
  margin: 0;
  font-family: "Space Grotesk", sans-serif;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  font-size: 0.8rem;
  color: var(--primary-strong);
}

h1 {
  margin: 0.68rem 0 0;
  font-size: clamp(1.58rem, 3.8vw, 2.7rem);
  line-height: 1.1;
}

h1 span {
  display: block;
  color: var(--primary-strong);
}

.hero-desc {
  margin: 1rem 0 0;
  color: var(--muted);
  line-height: 1.68;
  max-width: 56ch;
}

.hero-actions,
.download-actions {
  margin-top: 1.1rem;
  display: flex;
  flex-wrap: wrap;
  gap: 0.7rem;
}

.btn {
  border-radius: 999px;
  text-decoration: none;
  border: 1px solid transparent;
  padding: 0.62rem 1rem;
  cursor: pointer;
  font: inherit;
  font-weight: 700;
  letter-spacing: 0.01em;
  transition: transform 0.18s ease, box-shadow 0.2s ease;
}

.btn:hover {
  transform: translateY(-1px);
}

.btn-primary {
  background: linear-gradient(120deg, var(--primary), var(--primary-strong));
  color: #f8fbff;
  box-shadow: 0 12px 24px rgba(15, 99, 255, 0.28);
}

.btn-soft {
  background: var(--soft);
  border-color: #c9d8fa;
  color: var(--ink);
}

.btn-ghost {
  background: #f6fafc;
  border-color: #cde0f0;
  color: #123f78;
}

.hero-panel {
  padding: 1rem;
  display: grid;
  gap: 0.76rem;
  align-content: start;
}

.stat-card {
  border: 1px solid #d9e5f8;
  border-radius: 16px;
  background: linear-gradient(180deg, #fcfdff, #f0f5ff);
  padding: 0.9rem;
}

.stat-label {
  display: block;
  color: var(--muted);
  font-size: 0.78rem;
}

.stat-card strong {
  margin-top: 0.28rem;
  display: block;
  font-size: 0.98rem;
}

.features,
.gallery-card,
.download-card,
.faq-card {
  padding: clamp(1.05rem, 2vw, 1.55rem);
}

h2 {
  margin: 0;
  font-size: clamp(1.24rem, 2.8vw, 1.8rem);
}

.feature-grid {
  margin-top: 1rem;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 0.82rem;
}

.feature-card {
  border: 1px solid #dde7f7;
  border-radius: 16px;
  background: linear-gradient(170deg, #ffffff, #f4f8ff);
  padding: 0.95rem;
}

.feature-card h3 {
  margin: 0;
  font-size: 1rem;
}

.feature-card p {
  margin: 0.45rem 0 0;
  font-size: 0.92rem;
  color: var(--muted);
  line-height: 1.62;
}

.gallery-card {
  max-width: 840px;
  margin: 0 auto;
}

.gallery-head p {
  margin: 0.2rem 0 0;
  color: var(--muted);
}

.gallery-tabs {
  margin-top: 0.9rem;
  display: inline-flex;
  gap: 0.45rem;
  padding: 0.25rem;
  border: 1px solid #d6e4f7;
  border-radius: 999px;
  background: #f4f8ff;
}

.gallery-tab {
  border: 0;
  background: transparent;
  color: #4b6187;
  font-weight: 700;
  border-radius: 999px;
  padding: 0.35rem 0.7rem;
  cursor: pointer;
}

.gallery-tab.is-active {
  background: #dce9ff;
  color: #0d4cc1;
}

.gallery-viewer {
  margin-top: 0.95rem;
  display: grid;
  grid-template-columns: 34px minmax(0, 1fr) 34px;
  align-items: center;
  gap: 0.5rem;
}

.page-btn {
  width: 34px;
  height: 34px;
  border: 1px solid #bfd3ff;
  border-radius: 999px;
  background: linear-gradient(180deg, #f5f9ff, #e8f0ff);
  color: #1148b5;
  font-size: 1.12rem;
  line-height: 1;
  cursor: pointer;
}

.page-frame {
  margin: 0;
  border-radius: 18px;
  border: 1px solid #d7e2f7;
  background: linear-gradient(160deg, #ffffff, #f3f7ff);
  padding: 0.3rem;
  min-height: clamp(210px, 27vw, 360px);
  display: grid;
  place-items: center;
  overflow: hidden;
  perspective: 1200px;
}

.page-frame img {
  width: 100%;
  height: 100%;
  object-fit: contain;
  border-radius: 12px;
  transform-origin: center;
}

.page-frame.is-flipping-next img {
  animation: page-next 360ms ease;
}

.page-frame.is-flipping-prev img {
  animation: page-prev 360ms ease;
}

@keyframes page-next {
  0% { transform: rotateY(0deg) scale(1); opacity: 1; }
  49% { transform: rotateY(88deg) scale(0.98); opacity: 0.35; }
  50% { transform: rotateY(-88deg) scale(0.98); opacity: 0.35; }
  100% { transform: rotateY(0deg) scale(1); opacity: 1; }
}

@keyframes page-prev {
  0% { transform: rotateY(0deg) scale(1); opacity: 1; }
  49% { transform: rotateY(-88deg) scale(0.98); opacity: 0.35; }
  50% { transform: rotateY(88deg) scale(0.98); opacity: 0.35; }
  100% { transform: rotateY(0deg) scale(1); opacity: 1; }
}

.gallery-foot {
  margin-top: 0.8rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.8rem;
}

#page-index {
  color: #3f4f73;
  font-weight: 700;
  font-family: "Space Grotesk", "Noto Sans SC", sans-serif;
}

.page-dots {
  display: flex;
  align-items: center;
  gap: 0.45rem;
  flex-wrap: wrap;
}

.page-dots button {
  width: 9px;
  height: 9px;
  border-radius: 999px;
  border: none;
  background: #b5c7eb;
  cursor: pointer;
  padding: 0;
}

.page-dots button.is-active {
  background: #0f63ff;
  transform: scale(1.3);
}

.download-card p {
  color: var(--muted);
  line-height: 1.66;
}

#copy-status {
  display: block;
  margin-top: 0.6rem;
  color: var(--primary-strong);
  min-height: 1.2em;
}

.faq-list {
  margin-top: 0.9rem;
  display: grid;
  gap: 0.55rem;
}

.faq-list details {
  border: 1px solid #dbe6f7;
  border-radius: 12px;
  background: #f8fbff;
  padding: 0.7rem 0.8rem;
}

.faq-list summary {
  font-weight: 700;
  cursor: pointer;
}

.faq-list p {
  margin: 0.45rem 0 0;
  color: var(--muted);
  line-height: 1.6;
}

.site-footer {
  text-align: center;
  color: #506185;
  padding: 1.3rem 1rem 2.1rem;
  font-size: 0.92rem;
}

.reveal {
  opacity: 0;
  transform: translateY(16px);
  transition: opacity 0.4s ease, transform 0.4s ease;
}

.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}

@media (max-width: 920px) {
  .hero {
    grid-template-columns: 1fr;
  }

  .feature-grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 560px) {
  main {
    width: calc(100% - 1rem);
    gap: 0.9rem;
  }

  .site-header {
    padding: 0.72rem 0.7rem;
  }

  .lang-btn {
    padding: 0.31rem 0.49rem;
    font-size: 0.78rem;
  }

  .hero-copy,
  .hero-panel,
  .features,
  .gallery-card,
  .download-card,
  .faq-card {
    border-radius: 18px;
  }

  .gallery-viewer {
    grid-template-columns: 1fr;
  }

  .page-btn {
    width: 100%;
    border-radius: 12px;
    height: 34px;
    font-size: 1.05rem;
  }

  .gallery-tabs {
    width: 100%;
    justify-content: space-between;
  }

  .download-actions .btn {
    width: 100%;
    justify-content: center;
  }
}